Light weight doctor construction



y 1964 D. J. MILLIKEN 3,131,416

LIGHT WEIGHT DOCTOR CONSTRUCTION Filed Dec. 14, 1962 INVENTOR DAVID J. MILLIKEN ATTORNEY United States Patent Oflice 3,131,416 Patented May 5., 1964 3,131,416 LIGHT WEIGHT DOCTOR CONSTRUCTION David J. Milliken, Northboro, Mass., assignor to Lodd ng Engineering Corporation, Auburn, Mass., a corporation of Massachusetts Filed Dec. 14, 1962, Ser. No. 244,635 7 Claims. (Cl. -25651) This invention relates to a new and improved light weight doctor construction for supporting doctor blades and particularly to a construction providing for a light weight supporting means for the blade, together with means for minimizing vibration therein.

The advantages of a light weight construction as to the doctor are obvious, but the lighter the construction the more vibration ordinarily occurs, and it is therefore advantageous to provide a lightweight construction which however does not vibrate to any appreciable degree deleterious to the machine or the operation of the doctor.

The invention involved resides primarily in a support or holder for the blade comprising an elongated hollow member of any desired or convenient cross sectional design and including a doctor back which is arranged transversely thereof and across the same, being arranged preferably diametrically if the tubular supporting member should be for instance in cylindrical form, said doctor back extending out at opposite side edges of said hollow member and having at the operative side thereof a blade holder with a blade on it, said hollow tubular member being preferably of aluminum of aluminum alloy greatly reducing the weight of the usual blade holding construction.

In forming the construction of such light weight as above described, it has been found that it will sometimes vibrate to an undesirable degree and this invention therefore contemplates the provision of means to prevent such vibration, and in this case the hollow member is filled with an expanded or foamed plastic material, this being an extremely light weight cellular material which is easily applied to the construction simply by pouring it into the tubular member when the plastic material is in liquid form; as it solidifies it expands, forming a cellular filler for the hollow member, and this has been found to eliminate undesirable vibration in a light weight doctor construction as described.

The invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly set forth in the appended claims.

Reference is to be had to the accompanying drawings, in which FIG. 1 is a view in elevation with parts cut away illustrating the invention;

FIG. 2 is a section on line 2-2 of FIG. 1, and

FIG. 3 is an end view, looking in the direction of arrow 3 in FIG. 1.

Referring now to the drawings in detail, the reference numeral 10 indicates a roll surface which is to be doctored. This roll is mounted in any way desired and of course extends across the machine in the usual way. On the machine frame at opposite sides thereof there are mounted brackets 12 upon which are mounted doctor journal bearings 14 swivelly mounting doctor journals 16 and these are pivoted on their axis by means of for instance a hydraulic or pneumatic cylinder 18 (see FIG. 3) mounted in any way desired on the machine frame as for instance upon the structural brackets at 20 and having a pivot connection 22 with an arm 24 mounted at 26 fast to journal 16 in the usual way. Brackets 20 may be suspended from brackets 12.

The two journals 16 pivotally mount between them an elongated hollow tubular member generally indicated by the reference numeral 28. This is preferably made of aluminum or other light weight material for the purpose of reducing the over-all weight of the usual doctor back. This tubular member 28 may be of any cross sectional form. It is here shown as cylindrical and it extends from end-to-end of the roll 10.

Diametrically mounted the entire length of this tubing 28 there is a plate indicated at 30 and it will be seen in FIGS. 2 and 3 that it extends completely across the tubular member 28 essentially forming the latter into two halves, and as a matter of fact the tubular member 28 may be fabricated in this manner. In any event, the plate 30 extends at 32 outwardly diametrically of tubular member 28 and carries at its forward edge the blade holder 34 which in turn carries a blade 36 more or less in the usual way.

The ends of the tubular member 28 are closed by end plates as is indicated at 38 and the tubular member 28 is completely filled with a very light weight cellular expanded plastic material, these being well known materials. For example, polystyrene or polyurethane or polyethylene can be used. These are very easy to apply to the tube inasmuch as before the end plates 38 at one end only of the doctor back are assembled, the liquid plastic is poured into the tubular member at each side of the plate 30 and upon hardening it expands as is well known in the art into a cellular, plastic material and fills the member 28 with a bulky material of extremely light weight. The effect of this is that the tubular member 28 is damped to such a degree that unwanted vibration is minimized to an extent to allow the device to operate freely and at all times in the usual manner of doctor blades of the prior art regardless of its extreme light weight.

This invention therefore will be seen to provide an extremely lightweight doctor supporting construction which however obviates unwanted vibration which occurs when the supporting construction is made of light weight ma terials, and without the necessity of providing extra dead weight for the purpose of dampening vibrations and avoiding the use of all other cumbersome and expensive means for accomplishing the purpose.

In some cases a stiff cellular material is found to be advantageous, such as polystyrene, but also softer spongy cellular materials such as polyurethane are used to advantage.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

l. A doctor blade supporting construction comprising a light weight elongated hollow member, a plate extending transversely across and through said hollow member and partially exteriorly thereof in the same plane along one side edge, a doctor blade holder on the extending edge of said plate, a doctor blade on said holder, means fixedly mounting the holder directly onto the plate, means fixedly mounting the blade on the holder, the blade thereby being in supported, fixed relation to the plate, and means to damp the hollow member against-vibration, said means comprising a cellular plastic material of light weight substantially filling the hollow member.

2. The doctor construction of claim 1 wherein said plastic material is substantially rigid.

3. The doctor construction of claim 1 wherein said plastic material is substantially yieldable.

4. The doctor construction of claim 1 wherein the plate is rectangular and extends completely diametrically through the hollow member.

5. The doctor construction of claim 1 wherein the plate is rectangular and extends completely diametrically through the hollow member, said tubular member being substantially cylindrical.

6. The doctor construction recited in claim 1 including journals pivot-ally mounting said hollow member, said journals being offset relative to the axis of said hollow member.

7. The doctor construction recited in claim 1 wherein said hollow member is substantially cylindrical, and including a journal at each end thereof, said journals being offset with respect to the axis of said hollow cylindrical member and including means for swinging said journals to swing the hollow member and with it the doctor blade.

Heisel Dec. 18, 1928 Holcomb Oct. 5, 1943 OTHER REFERENCES British Plastics (page 3), January 1956. 

1. A DOCTOR BLADE SUPPORTING CONSTRUCTION COMPRISING A LIGHT WEIGHT ELONGATED HOLLOW MEMBER, A PLATE EXTENDING TRANSVERSELY ACROSS AND THROUGH SAID HOLLOW MEMBER AND PARTIALLY EXTERIORLY THEREOF IN THE SAME PLANE ALONG ONE SIDE EDGE, A DOCTOR BLADE HOLDER ON THE EXTENDING EDGE OF SAID PLATE, A DOCTOR BLADE ON SAID HOLDER, MEANS FIXEDLY MOUNTING THE HOLDER DIRECTLY ONTO THE PLATE, MEANS FIXEDLY MOUNTING THE BLADE ON THE HOLDER, THE BLADE THEREBY BEING IN SUPPORTED, FIXED RELATION TO THE PLATE, AND MEANS TO DAMP THE HOLLOW MEMBER AGAINST VIBRATION, SAID MEANS COMPRISING A CELLULAR PLASTIC MATERIAL OF LIGHT WEIGHT SUBSTANTIALLY FILLING THE HOLLOW MEMBER. 